1. Field of the Invention
The present invention generally relates to a cordless charging apparatus, and more particularly, to a cordless charging apparatus for dispersing heat generated during cordless charging of a portable electronic device.
2. Description of the Related Art
Generally, a portable electronic device refers to a device by which a user accesses various contents while carrying the device, such as a portable terminal, an MP3 player, a Portable Multimedia Player (PMP), or an electronic book. Especially, the portable terminal, usually referred to as a smart phone, has various and diverse functions. The portable terminal has, for example, a Near Field Communication (NFC) module mounted thereon for a certification of a security card of a user certification, a transportation card, a credit card and the like, or a user certification. The portable terminal includes a separate antenna in order to carry out an NFC function. The NFC technology is generally disclosed in Korean Laid-Open Patent Publication No. 2009-126323.
Further, a portable electronic device typically includes a detachable or embedded battery to supply the device with electric power, and a user charges a battery based on a remaining amount of electric power in the battery and uses the portable device. Typical battery charging is classified into wired cable charging and cordless charging. Generally, the wired cable charging has been popularized, but recently various technologies relating to cordless charging have been developed. The cordless charging technologies include an inductive coupling scheme using a magnetic field, a capacitive coupling scheme using an electric field, and a radio frequency wave radiation scheme, such as disclosed in Korean Laid-Open Patent Publication No. 2008-32519.
FIG. 1 schematically illustrates a cordless charging unit for cordless charging, which is embedded in a portable electronic device. FIG. 2 illustrates the portable electronic device having the cordless charging unit and a cordless charging apparatus such as an external charging pad. Referring to FIGS. 1 and 2, the cordless charging device 30 includes a cordless charging unit 12 provided in the portable electronic device 10, and an external charging pad 20 for charging a battery according to a transmission and reception of signals to/from the cordless charging unit 12 on which the portable electronic device 10 is placed. The portable electronic device 10 has a battery (not shown) for supplying electric power thereto. Further, the portable electronic device 10 includes an NFC antenna element 13 in the general form of a loop antenna and the cordless charging unit 12, which are mounted on a side of the battery in the portable electronic device including an NFC function and a cordless charging function. A driving circuit unit 11 is provided on an upper side of the NFC antenna element 13 and the cordless charging unit 12, and connected to the NFC antenna element 13 and the cordless charging unit 12. Furthermore, a shielding material 14 is used in order to shield interference between the NFC antenna element 13 and the cordless charging unit 12 which may be caused by an operation of the NFC antenna element 13 and the cordless charging unit 12, or in order to shield an effect which the operation of the NFC antenna element 13 and the cordless charging unit 12 has on other circuit units in the portable electronic device.
The portable electronic device 10 is provided with a separate charging pad 20 for charging a battery of the portable electronic device 10 which is placed thereon. When the portable electronic device 10 is placed on the charging pad 20 in order to charge the battery, the battery is charged by a cordless resonance between the cordless charging unit 12 and the charging pad 20. However, while the portable electronic device 10 is placed on the charging pad 20 and the battery is charged, the driving circuit unit 11 generates heat with a high temperature. Various dispersing units are provided in the portable electronic device 10, particularly near the driving circuit unit 11, in order to disperse high-temperature heat.
However, the heat generated in the driving circuit unit 11 is typically dispersed into the portable electronic device 10, and a hotspot region where the heat is particularly concentrated on only a part around the driving circuit unit 11 is created and generates heat. Internal modules such as an antenna, a loop antenna and the NFC antenna element 13, which are used for communication of the portable electronic device 10, are disposed around the driving circuit unit 11. Accordingly, the internal modules may have a low performance or be damaged by the high temperature heat generated by the driving circuit unit 11. For example, there are disadvantages in that the NFC antenna element 13 deteriorates due to the high temperature heat, and cordless charging efficiency is lowered. Also, there is problem in that poor charging results.
Moreover, the heat generated in the driving circuit unit 11 is not efficiently dispersed and generates a heat island at which the high temperature heat is collected since the generated heat is not discharged due to spatial limitations in the portable electronic device 10. Therefore, there is a disadvantage in that the heat is concentrated on the driving circuit unit 11 and causes deterioration of the performance of the driving circuit unit 11. Furthermore, in order to disperse the generated heat, a material such as graphite and the like may be disposed on the driving circuit unit 11 so as to disperse the heat. However, there is a problem in that the dispersion of the generated heat is not normally established because of the limitation of the space for dispersing the generated heat in the portable electronic device 10. In addition, it is difficult to secure a space for dispersing heat due to a restricted internal space, as a variety of internal modules are disposed in the portable electronic device 10, and the portable electronic device 10 is slimmed down and miniaturized.